diff --git a/main/snprintf.c b/main/snprintf.c
index 2bf871a9fb2..c52a09f1578 100644
--- a/main/snprintf.c
+++ b/main/snprintf.c
@@ -565,14 +565,6 @@ typedef struct buf_area buffy;
 	}					\
 	while ( (size_t)width > len )
 
-/*
- * Prefix the character ch to the string str
- * Increase length
- * Set the has_prefix flag
- */
-#define PREFIX( str, length, ch )	 *--str = ch ; length++ ; has_prefix = true
-
-
 /*
  * Do format conversion placing the output in buffer
  */